The instrumentation requested in this proposal will provide a unique capability for a group of NIH supported investigators who have a common need for highly sensitive analytical and structural characterization methods for complex lipids and oligosaccharides. The PI and collaborators, with the existing Finnigan 4500 mass spectrometer and a moving belt liquid chromatographic interface, have demonstrated that the on-line LC/MS analysis of underivatized phospholipids and glycolipids can provide rapid analytical and structural information previously not possible. The mass range of the Finnigan 4500 (1000 u) is a severe limitation to the exploitation of LC/MS for complex lipids which have molecular weights above 1000 daltons. There are also pressing demands for access to the existing mass spectrometry facilities from ongoing research programs. The proposed acquisition of a VG MM707E (formerly referred to as 7070E-HF) high mass range mass spectrometer (HF-MS) with DCI and LC interface will provide a unique capability in the Boston area for on line LC/MS with high mass analysis and belt FAB-ionization or in-source flash evaporation. The existing instrumentation will be freed for research programs requiring MS analysis of low molecular weight materials. The new instrumentation will directly and uniquely support the needs of research programs described in the application i.e. methods development (McCluer, et al), analysis and structural elucidation of neutral glycosphingolipids (Schwarting, McCluer and Raghavan), gangliosides (McCluer, Jungalwala and Schwarting) complex sulfoglycolipids in metachromatic leucodystrophy (Kolodny), phospholipid analysis related to regulation of myelinogenesis and development of brain tumors (Jungalwala) and oligosaccharide analysis related to mannosidoses (Daniel). Thus, this shared advanced HF-MS with DCI and LC interfacing capability will serve the needs and enhance the progress of these ongoing NIH supported research programs and will undoubtedly contribute to the pursuit of new research goals previously unapproachable.